The Effect of Homoeologous Meiotic Pairing in Tetraploid Hordeum bulbosum L. × H. vulgare L. Hybrids on Alien Introgressions in Offspring

2016 ◽  
Vol 150 (2) ◽  
pp. 139-149 ◽  
Author(s):  
Margret Scholz ◽  
Galina Pendinen
Keyword(s):  
Interspecific Hybrids ◽  
In Situ Hybridisation ◽  
Basic Material ◽  
Meiotic Pairing ◽  
Hordeum Bulbosum ◽  
Homoeologous Pairing ◽  
Introgression Breeding ◽  
The Individual ◽  
Pairing Behaviour

The pairing behaviour of the individual chromosome arms of Hordeum vulgare (Hv) with their homoeologous arms of H. bulbosum (Hb) at metaphase I of meiosis in tetraploid Hb × Hv hybrids and the frequencies of recombined Hv chromosome arms in selfed offspring were studied on differentially visualized chromosomes after fluorescent in situ hybridisation. The frequencies of paired Hv-Hb arms in the F2 and F3 hybrids were correlated with the frequencies of recombined Hv chromosomes in progenies. Self-generation of hybrids, the number of Hv and Hb chromosomes, and the number of recombined Hv chromosomes of the hybrids strongly influenced the Hv-Hb pairing frequency in meiosis. Within the offspring of F2 and F3 hybrids both Hv plants and hybrids were detected. In contrast, all progenies of the F4 hybrid were hybrids which exhibited centromere misdivisions. The highest frequencies of homoeologous pairing in hybrids and most recombinants were obtained for the barley chromosome 1HL. Recombinants for 4HL, 5HS, 6HS, and 7HS were rarely found. Meiotic pairing and recombinants involving chromosome 1HS were never observed. The results of this study demonstrate that fertile tetraploid interspecific hybrids with a high intergenomic pairing at meiosis are valuable basic material for introgression breeding in barley.

Meiosis in interspecific Hordeum hybrids. I. Diploid combinations

1986 ◽  
Vol 28 (4) ◽  
pp. 525-535 ◽  
Author(s):  
Roland Von Bothmer ◽  
Jan Flink ◽  
Thomas Landström
Keyword(s):  
Interspecific Hybrids ◽  
Genomic Structure ◽  
Genetic Regulation ◽  
The Other ◽  
South American ◽  
Meiotic Pairing ◽  
Hordeum Bulbosum ◽  
High Affinity ◽  
Hordeum Species ◽  
Pairing Behaviour

The meiotic pairing behaviour of 39 new interspecific combinations between diploid Hordeum species are reported. On the basis of this data, four "basic genomes" are probably present in the genus. Hordeum bulbosum and H. vulgare have the same genome (I); H. marinum ("X") and H. murinum ("Y") each have one distinct genome. All other diploid taxa have either the same or a somewhat modified form of genome H. In this latter group of diploids, the South American taxa together with H. pusillum and H. intercedens in North America constitue a homogeneous group with respect to genomic structure, which differs somewhat from that found in the other Asiatic and North American species. Hordeum roshevitzii from Central Asia is unique, showing high affinity to both the Asiatic and to the American taxa. Evidence suggesting genetic regulation of chromosome pairing (both pairing promoting and pairing reducing) was obtained from a number of the diploid hybrids.Key words: Hordeum, interspecific hybrids, meiosis, diploids.

Identification of all chromosome arms and their involvement in meiotic homoeologous associations at metaphase I in 2 Hordeum vulgare L. × Hordeum bulbosum L. hybrids

Genome ◽  
2006 ◽  
Vol 49 (1) ◽  
pp. 73-78 ◽  
Author(s):  
R Pickering ◽  
S Klatte ◽  
R C Butler
Keyword(s):  
In Situ Hybridization ◽  
Hordeum Vulgare ◽  
Fluorescence In Situ Hybridization ◽  
Interspecific Hybrids ◽  
Association Studies ◽  
Hordeum Bulbosum ◽  
Hordeum Vulgare L ◽  
Chromosome Addition ◽  
Chromosome Associations

We have identified all Hordeum bulbosum chromosomes in 2 diploid Hordeum vulgare × Hordeum bulbosum hybrids using suitable probes and fluorescence in situ hybridization. Using the parental idiograms allowed us to carry out a full analysis of chromosome associations among all chromosome arms in the hybrids. Association frequencies were generally lower for the short arms than for the long arms. There were also significant differences among the chromosome arms in association frequencies, partly correlated with the absolute length of the chromosome arm, as well as with the frequency of recombinant lines, which were recovered from partially fertile interspecific hybrids. The H. bulbosum idiogram will be useful for further chromosome association studies and will enable the identification of H. bulbosum chromosomes involved in chromosome addition or substitution lines.Key words: Hordeum vulgare, Hordeum bulbosum, interspecific hybrids, chromosome associations, meiosis, fluorescence in situ hybridization.

scholarly journals The position of a locus on chromosome 5B of Triticum aestivum affecting homoeologous meiotic pairing

1971 ◽  
Vol 18 (3) ◽  
pp. 329-339 ◽  
Author(s):  
A. M. Wall ◽  
Ralph Riley ◽  
M. D. Gale
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Single Locus ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Chromosome 5B ◽  
Homoeologous Chromosome Pairing ◽  
Mutant Locus ◽  
Homoeologous Chromosomes ◽  
Pairing Behaviour

SUMMARYAn investigation was made of the chromosomal position of the mutant locus, in Mutant 10/13 of Triticum aestivum (2n = 6x = 42), affecting homoeologous chromosome pairing at meiosis. In hybrids between Mutant 10/13 and rye (Secale cereale 2n = 14), homoeologous chromosomes frequently pair at meiosis although normally, in wheat-rye hybrids, this happens infrequently.The association of the mutant condition with chromosome 5B was determined by (i) the absence of segregation in hybrids obtained when Mutant 10/13 monosomic 5B was pollinated by rye; (ii) the occurrence of trisomie segregation for pairing behaviour in 28-chromosome wheat-rye hybrids, obtained from SB trisomie wheat parents with two 5B chromosome from a non-mutant and one from a mutant parent; (iii) the absence of segregation for pairing behaviour in the 29-chromosome wheat-rye hybrids obtained from the same trisomie wheat parents.The alternative pairing behaviours segregated independently of the centromere when wheat plants that were simultaneously heteromorphic, 5BL telocentric/5B complete, and heterozygous for the Mutant 10/13 state, were pollinated by rye. The alternative chromosome-pairing patterns segregated to give a ratio not different from 1:1, so that the association of homoeologous pairing with Mutant 10/13 probably derived from the occurrence of mutation at a single locus on 5BL. In the disomic heteromorphic state, 5BL was 91 map units in length.Trisomie wheats with two complete 5B chromosomes and one 5BL telocentric, that were also heterozygous for the Mutant 10/13 condition, were pollinated by rye. Among the resulting 28-chromosome hybrids there was a 2:1 segregation of hybrids with low pairing: high (homoeologous) pairing and also of hybrids with complete 5B: telocentric 5BL. However, there was no evidence of linkage in this trisomie segregation. All the 29-chromosome hybrids from this cross had low pairing and it could be concluded that the single mutant allele, in Mutant 10/13, was recessive. In the trisomie condition, relative to a simplex situation, 5BL was 33·05 map units in length.The critical locus on 5BL was designated Pairing homoeologous. The normal dominant allele was symbolized Ph and the recessive allele, in Mutant 10/13, ph.The prevention of homoeologous pairing by the activity of a single locus makes the evolution of the regular meiotic behaviour of T. aestivum more readily comprehensible.

Combining mutations for the two homoeologous pairing suppressor genes Ph1 and Ph2 in common wheat and in hybrids with alien Triticeae

Genome ◽  
1993 ◽  
Vol 36 (2) ◽  
pp. 377-386 ◽  
Author(s):  
Carla Ceoloni ◽  
Paolo Donini
Keyword(s):  
Common Wheat ◽  
Interspecific Hybrids ◽  
Double Mutant ◽  
Homoeologous Pairing ◽  
Suppressor Genes ◽  
Plant Variation ◽  
Significant Difference ◽  
Chromosome Arm ◽  
Aegilops Variabilis ◽  
Pairing Behaviour

Two lines of common wheat cv. Chinese Spring, carrying simultaneous mutations for the two major homoeologous pairing wheat suppressor genes Ph1 and Ph2 have been developed and their pairing behaviour compared with that of the ph1b mutant of the same cultivar. Besides carrying the ph1b mutation, the first double mutant line lacked the chromosome arm pair 3DS, containing Ph2, whereas the second had a euploid constitution and carried the ph1b allele on 3DS. Hybrids of Aegilops variabilis and Secale cereale with mono-5B (ph1b) and 3D/3DL plants have also been obtained, where the 3D versus 3DL presence marked the two pairing alternatives (ph1b only and ph1b + Ph2−, respectively). In the wheat × Ae. variabilis hybrids, an 8% increase in total chromosome pairing, almost entirely ascribable to an increment of multivalent associations, was observed in the 2n = 34 + t plants with respect to their 2n = 35 sibs. The number of bivalents showed no significant difference, but a tendency towards a decrease, which was significant for the rod types, was exhibited by the Ph2− plants. A weaker but similar effect was observed in wheat itself. The different mutants, in fact, showed a similar percentage of paired chromosomes but varied in their pairing pattern. A significant reduction in the number of bivalents, owing to a decrease of the rings, only partly compensated for by an increase of the rods, was observed in the double mutants. They also exhibited an increase in the multivalent fraction, which was significant for the most complex associations. In both common wheat and its hybrids with Ae. variabilis the addition of a ph2 mutation thus seems to reinforce the ph1b effect in promoting homoeologous pairing. On the other hand, such an effect was not noticed in the wheat × S. cereale hybrids. However, possible quantitative differences could have been masked by the considerable plant-to-plant variation and potential differences in relative incidence of wheat–wheat versus wheat–rye associations were undetectable in the Feulgen-stained materials analyzed.Key words: common wheat, interspecific hybrids, homoeologous pairing, Ph mutations.

Meiotic duration in wheat genotypes with or without homoeologous meiotic chromosome pairing

1974 ◽  
Vol 187 (1087) ◽  
pp. 191-207 ◽  
Keyword(s):  
Chromosome Pairing ◽  
Chinese Spring ◽  
Meiotic Chromosome ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Meiotic Chromosome Pairing ◽  
Chromosome 5B ◽  
Homoeologous Chromosome Pairing ◽  
The Cross ◽  
Pairing Behaviour

In order to investigate the possible relation between meiotic time and meiotic chromosome pairing behaviour, meiosis was timed in various forms of wheat and wheat hybrids. First, meiosis was timed in ten Triticum aestivum (var. Chinese Spring) genotypes with different chromosome constitutions which differed widely in the meiotic pairing behaviour. Secondly, in order to escape from the disadvantage of aneuploid material, meiosis was also timed in plants which differed in the extent of homoeologous pairing because of the activities of different alleles at one or two loci. For this experiment use was made of F 1 -hybrids from the cross T. aestivum x Aegilops mutica which, although they all have 28 chromosomes, differ widely in the amount of homoeologous pairing. Thirdly, meiosis was also timed in 28-chromosome and 29-chromosome plants derived from the cross between rye (Secale cereale) x 43-chromosome T. aestivum containing a single Ae. mutica addition chromosome known to carry genes which greatly affect the level of homoeologous pairing in wheat. Although the 28-chromosome plants display very little pairing (chiasma frequency per cell (c. f.) = 0.5) while 29-chromosome plants display a much higher amount of pairing (c. f. = 7.8) no difference in meiotic time was detected between them. Similarly, the duration of meiosis was not significantly different between the three types of F 1 -hybrids between T. aestivum x Ae. mutica which had chiasma frequencies of 14.3, 7.4 and 0.9. Thus, these results agree in showing that there was no correlation between the duration of meiosis and the amount of homoeologous chromosome pairing. The results obtained for genotypes of Chinese Spring also provided no evidence to support the notion that there is a relation between the level of chromosome pairing and the duration of the pairing process. Consequently some doubt must be cast upon the idea that the time available for pairing is limiting to the pairing process. It was shown that individual wheat chromosomes in Chinese Spring differed in their effects on meiotic duration. For instance, the absence of chromosome 7B has no detectable effect on meiotic duration. The absence of chromosome 5B in two genotypes resulted in an increase in meiotic time from that found in euploid plants (24 h) to that found in tetraploid wheat species (about 30 h). By using plants ditelosomic for chromosome 5B L it was shown that most, if not all, of the genetic effects of chromosome 5B on meiotic time are determined by the short arm.

Meiosis in interspecific Hordeum hybrids. IV. Tetraploid (4x × 4x) hybrids

Genome ◽  
1988 ◽  
Vol 30 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Roland von Bothmer ◽  
Jan Flink ◽  
Tomas Landström
Keyword(s):  
Interspecific Hybrids ◽  
Genetic Regulation ◽  
The Other ◽  
Meiotic Pairing ◽  
Genomic Constitution ◽  
Hordeum Species ◽  
Hordeum Brevisubulatum ◽  
Pairing Behaviour

The meiotic pairing behaviour of 31 interspecific combinations of tetraploid Hordeum species are reported. The autoploid H. bulbosum with the II genomic constitution has no homology to the other species. The constitution of tetraploid H. murinum is not clear, but it is not homologous to other tetraploids. Hordeum marinum is a probable autoploid (XX) but with a very strong genetic regulation of pairing. The X genome is possibly found in H. secalinum and H. capense, both of which also possess the H genome in several diploids. Hordeum fuegianum, H. tetraploidum, H. jubatum, H. brachyantherum, and H. roshevitzii are segmental alloploids all with the same two partly homoeologous genomes. Hordeum depressum is probably a segmental alloploid with the H genome and with a very strong pairing regulation. Hordeum brevisubulatum is a pure autoploid with two homologous H genomes.Key words: Hordeum, interspecific hybrids, meiosis, tetraploids.

Bio-P and non-bio-P bacteria identification by a novel microbial approach

1999 ◽  
Vol 39 (6) ◽  
pp. 13-20 ◽  
Author(s):  
Philip L. Bond ◽  
Jürg Keller ◽  
Linda L. Blackall
Keyword(s):  
In Situ Hybridisation ◽  
Microbial Populations ◽  
Biological Phosphorus Removal ◽  
Gram Positive Bacteria ◽  
P Content ◽  
Identification Of Bacteria ◽  
Widespread Belief ◽  
Biological Phosphorus ◽  
P Removal

Culturing bacteria from activated sludge with enhanced biological phosphorus removal (EBPR) has strongly implicated Acinetobacter with the process. However, using fluorescent in-situ hybridisation (FISH) probing to analyse microbial populations, we have shown evidence opposing this widespread belief. We describe the phosphorus (P) removing performance and microbial population analyses of sludges obtained in a laboratory scale EBPR reactor. Two sludges with extremely high P removing capabilities were examined, the P content of these sludges was 8.6% (P sludge) and 12.3% (S sludge) of the MLSS. Identification of bacteria using FISH probing indicated both sludges were dominated by microbes from the beta proteobacteria and high mol% G+C Gram positive bacteria. Acinetobacter could make up only a small proportion of the cells in these sludges. Sludge with extremely poor P removal (P content of 1.5%, referred to as T sludge) was then generated by reducing the P in the influent. Bacteria resembling the G-bacteria became abundant in this sludge and these were identified using FISH probing. The anaerobic transformations of the T and P sludges correlated well with that of the non-EBPR and EBPR biological models respectively, indicating that bacteria in the T sludge have the potential to inhibit P removal in EBPR systems.

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